This 1968 Mullard circuit detects fire by smoke using LDR-type sensors. The circuit makes use of transistors of the time that admit equivalents.
This circuit was found in Motorola documentation from 1966. The lamps are according to power and...
This circuit, which uses components still common today, was found in a 1997 documentation. It...
This circuit is intended to apply the music signal from a stereo to a telephone line for the...